On Mon, 12 Oct 2009, iceberg wrote: > KERNEL_VERSION: 2.6.31 > DESCRIBE: > In driver ./drivers/hid/hidraw.c in function hidraw_read may be > double mutex_lock: > > Path: > 1. line 50: begin first iteration of "while(ret==0)" > 2. line 52: first call to mutex_lock > 3. inner loop "while (list->head == list->tail)" does not change state > of mutex, because mutex_lock immediatelly follows mutex_unlock > 4. if we go to the second iteration of "while(ret == 0)" in > line 50 then there are second call to mutex_lock in line 52 (mutex > aquired twice). > > Second iteration of loop "while(ret==0)" is possible if local variable > ret is not changed at line 94: ret+=len - i.e. len==0; > Variable len may be zero if hidraw_read is called with count==0 or > list->buffer[list->tail].len == 0. Good catch. I will fix that up by moving the mutex_lock() so that it's locked before the loop is entered. Thanks, -- Jiri Kosina SUSE Labs, Novell Inc. -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
